1. Field of the Invention
The present invention relates to an image pickup unit including an image pickup device, an objective lens, and a prism having a reflective surface for bending an optical axis of the objective lens, and also to an endoscope.
2. Description of the Related Art
In medical fields or industrial fields, for example, in order to observe locations which are difficult to observe inside a body of a living organism or inside a structure or the like, an endoscope that includes an image pickup unit for picking up an optical image and that can be introduced into the living organism or the structure from outside is utilized to perform such observation.
An image pickup unit of an endoscope includes an objective lens that forms an object image, and an image pickup device that is commonly referred to as a CCD (charge coupled device) or a CMOS (complementary metal-oxide semiconductor) sensor or the like that is arranged on an image-forming surface of the objective lens.
For example, an image pickup unit disclosed in Japanese Patent Application Laid-Open Publication No. 11-352413 or Japanese Patent Application Laid-Open Publication No. 2009-58807 has a configuration in which a prism is arranged between an objective lens and an image pickup device, and an optical axis of the objective lens is bent by the prism. According to the image pickup unit disclosed in Japanese Patent Application Laid-Open Publication No. 11-352413 or Japanese Patent Application Laid-Open Publication No. 2009-58807, the prism is fixed inside a frame-shaped member.
An image pickup unit also includes a cable connection terminal portion to which an electrical cable is connected and an electronic component. For example, in the image pickup unit disclosed in Japanese Patent Application Laid-Open Publication No. 11-352413, a printed wiring board is provided on a rear face side of a reflective surface of the prism, and a cable connection terminal portion is formed on the printed wiring board. Further, in the image pickup unit disclosed in Japanese Patent Application Laid-Open Publication No. 2009-58807, a printed wiring board is extended to outside of a frame-shaped member that houses a prism and an image pickup device, and an electronic component is mounted thereon.